This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. A recurring observation in the study of reproductive proteins is their rapid, adaptive evolution. This phenomenon occurs in organisms as diverse as diatoms and humans. The long-term goal of our research is to understand the diversity of reproductive proteins and the functional consequences of their divergence, which could involve problems in fertility and speciation due to a mismatch of sperm-egg recognition molecules. We work with a variety of organisms, including Drosophila, abalone (Haliotis), and mammals. A common theme throughout our research is identifying genes subjected to positive selection (adaptive evolution), indicating potentially functionally important candidate genes.